What Tube Material ?

HighlandR · 17 August 2014, 16:05

Hi guys, just trying to figure out what material my sib is.

Will it be Hypalon or PVC ?

It is 3.8 meter length, with rigid keel.

I see that majority of modern boats this size have 3 tubes for back up, this one has only 2 tubes.

Should I be concerned about this from a safety point of view ?
Intend using it for sea fishing, a mile or off the coast.

What would be the typical course of action if puncturing 1 of the tubes ?

HighlandR · 18 August 2014, 14:39

Had a good search around on the forum and found that Hypalon will be coloured black on the inside surface, but PVC and also PU fabric will be same colour both sides.

There is no information at all online about this brand of sib.

The tubes are also red on the inside - which means either PVC or PU.

Is there any differences to be aware of between these 2 material with regards to general care / cleaning and maintenance from UV damage etc, also adhesives and repairs, or can they both be treated the same way ?

jyasaki · 18 August 2014, 14:54

PU fabric on consumer boats is relatively new (compared to hypalon and PVC); if it comes down to "not hypalon", I'd guess PVC.

Looks like at least some adhesives are suitable for both PVC and Urethane:
Clifton Urethane Adhesive at nrs.com

You'll have to research what's available to you and whether it's suitable or not.

jky

HighlandR · 18 August 2014, 15:16

Thanks Jyasaki ! I'll check around see what is available here in UK.

Should I have any concerns about it having only 2 tubes rather than the usual 3+ ?

The Gurnard · 18 August 2014, 16:21

Quote:

Originally Posted by HighlandR

Should I have any concerns about it having only 2 tubes rather than the usual 3+ ?

Not sure anyone can answer that question for you HighlandR.... because what may concern one person may not concern another. It could depend on where or how you intend using it..ie if there are other boats around if a tube does go down. Are you likely to use sharp bait knives near the tubes etc

To help decide ..Consider what will happen if one of the two tubes does deflate unexpectedly at sea. The other tube will keep the boat afloat.. but the engine and passengers may well pull the floor under the water ..so you may end up in the sea, holding onto the remaining inflated tube until help arrived.

In a three section boat..there is more chance the boat will remain upright..(although it could still get water in the boat if the deflated tube couldn’t be help up to keep water out) So three tubes is preferable.

However, I imagine the chance of a tube suddenly deflating at sea is quite rare unless you hit a submerged object, the boat material is that old the seam splits..or you accidentally puncture it with something sharp like a knife. A fish hook would probably only cause a slow leak..so when you notice it going soft ..you would head for shore straight away.

If I was happy the material and seams were in good condition..I would use it..if other boats were in the same area .. but Im not scared of being in water if the rare event that the worst happened. If you are not happy with anything..dont go far from shore until you know it is reliable (from your photos..it looks old ?) If you are not happy then get another boat you are happy with. Compared to your peace of mind.. a new inflatable is not so expensive ?

My opinion only.. based on what I think may happen if you do burst a tube.. other may disagree.

Christopher · 18 August 2014, 16:24

If my memory serves me correctly these Nautylatex boats were built by Mirage in a range of sizes and definitely in Hypalon coated fabric. They only had one air chamber per side and I would not suggest going very far with only two air chambers. With one chamber suffering damage the boat would be virtually useless and I would urge extreme caution if you do intend to take it one mile offshore!!

ShinyShoe · 18 August 2014, 17:58

The valves are in a silly place too. Ideally if you had a small leak you should be able to top up on the way back. Good luck doing that ...

Commercially you'd risk assess this. What's the likelihood of failure and what's the likli consequence.

So older material makes the risk higher. Inability to top up and only 2 tubes.

So what can you do to mitigate risks... Either reduce likelihood or consequence. Reduce likelihood by inspect fabric, banning sharps, choosing launch sites carefully.

Reduce consequence by not being too far out, having multiple means of contacting help and signalling position. Carrying additional buoyancy couple of fenders? Personal gear etc.

You might spend as much reducing your consequence score to get the level down to the same as reducing the likelihood by buying modern fabric...

HighlandR · 18 August 2014, 20:00

Gurnard, thanks for taking the time to type that long reply.

Christopher, Shinyshoe I like your commercial approach ! I really appreciate the points and facts you have mentioned, they all make perfect sense.

My main concern is having one or both tubes deflate then sink, making the boat useless as you said Gurnard, and not being able to use the motor to head back in.

I have no issue at all with going into the water, i have kayak fished for a few years and going in doesn't bother me, but on the sib- my Father will be with me most of the time and I'd hate for him to have to end up in the water and have the stress of hanging onto 1 tube while waiting for help to arrive.

Add to that the motor being submerged and damaged etc...

The boat is old Gurnard - but I have no idea just how old it is, Christopher ??

Every seam looks to be in really good condition.. the underside all round the seams are fully bonded to the fabric, but I am not familiar enough with these things or with how the material will fail - especially with it being old.

If a seam was to fail - would it tear and seperate all the way along ? ( such as having the floor fall out the bottom for example ? )

I have various signalling devices that I use for the kayak, vhf, flares etc. Also have some fenders that could be fixed to the tubes....

My main concern is to keep both tubes afloat enough to support the 2 of us and the engine, so that we have enough buoyancy to motor back to shore and/or be somewhat more comfortable while waiting for help to arrive should the engine fail too.

The boat will be inflated and stored on the trailer permanently, so I'm thinking it would be possible to fill or partly fill ( partly fill so that the air can still inflate the tube without being distorted by too much foam ) each tube with some type of waterproof expanding foam, or possibly packaging foam peanuts of some type..

The valve holes are large enough to funnel a load of those peanuts inside......

That would give enough redundant buoyancy should the worst happen and both tubes get deflated...?

Is this a practical solution to the problem ?

ShinyShoe · 18 August 2014, 20:47

If the seam goes you'd often get a gap big enough to slide your hand in. Tubes permanently inflated is possibly good as soft before you go out should ring alarm bells...

Never heard of the bottom falling off a SIB.

People do do expanding foam. Not many. And they don't shout about how great it is... Foam selection would be important as some absorb water.

Packing chips almost certainly absorb water. Most are actually water soluble and edible ... Made from corn like skips crisps! How would you stop it leaking out the seam...

ShinyShoe · 18 August 2014, 20:49

Some form of inner tube makes sense for a burst seam... But not for a stabbing as the tube would be stabbed too...

HighlandR · 18 August 2014, 20:59

Hi Shinyshoe, just been reading about the peanuts that dissolve, but there are types that don't ( I don't know where to find them though ), I thought about a tear and the peanuts floating out all over the place..... perhaps some liquid latex poured in after the peanuts to help bind them together to a degree........... I wonder !

ShinyShoe · 18 August 2014, 21:15

No experience of liquid latex.

Crazy idea... Something like a long thin balloon pushed in through valve, inflated and tied. Repeat....
Now ballons normally deflate over time. Would it if the pressure outside it was higher (I.e. the inflated tube?)

Christopher · 18 August 2014, 21:16

Quote "The boat is old Gurnard - but I have no idea just how old it is Christopher ??"

They were made around 1972 to 1978.

Nos4r2 · 18 August 2014, 21:37

Don't consider innertubes-if the only company that made them (Gemini) is still about, you'll get ripped off. They were a regular occurence on here-people bought them then came here to complain about their boat being knackered.

Realistically, there's no solution that's safe and workable for the 2 chamber issue. If it bothers you that much, give the boat a damn good clean with TFR and sell it to buy something with 3+ chambers.

It's really only going to end up costing you time and money to result in something that you won't be able to sell if you mess around with foam/chips/any type of filler.

HighlandR · 18 August 2014, 22:29

Hi Nos, just been searching online and found a supplier of 20mm closed cell ( waterproof ) foam balls, the valves are 25mm dia. Would it be unsafe to fill the tubes with a good amount of these?

Other than the resale side of it Nos ( I guess the balls could be taken out again if i had 3 full days to spare ) I'm trying to weigh up the positives and negatives of having a thing that wont sink with my Father in it, the loss of resale value might still be worth it..... I'd gladly buy another second hand sib, but keep thinking....... even a brand new one with 3+ chambers still the risk is there to have a chamber burst ( especially if fishing over shallow grounds which we will be ) and be in the same situation and maybe wished I'd just filled the damn things with foam balls for peace of mind that it 99.9% wont sink ?

Nos4r2 · 18 August 2014, 23:17

You'd REALLY have to try to burst a chamber and with 3 chambers a boat will hold it's shape far better.

20mm foam balls are a false economy. Anything like that is. If you really want to make your current one safer, get some new valves and install them where you can pump the boat up while afloat, then carry a Clamseal (google it).

Really, there's so little risk of a 3 chamber sib sinking it's negligible. You're overthinking it.

ShinyShoe · 19 August 2014, 07:06

Yip... This is all trying to reduce the consequence score not the likelihood.

Not sure pumping a seam failure will achieve much but good suggestion on extra valves. I wasn't thinking of a Gemini tube but more a home bodge!

20mm balls... No good for a 21mm hole...

Still worried? You need an unsinkable hull either a foam filled GRP like a dory or a rotomould like FunYak...

Or... Operate in company...

ShinyShoe · 19 August 2014, 07:30

http://pages.ebay.com/link/?nav=item...542372&alt=web
Bodge?

Valve at front. Insert this through valve. Repeat with existing valve at rear.

Inflated this is 11 inch. So need a big split to come out. Stabbing puncture? Only loose one inner...

But... Not sure how its pressures would compare... Suspect you'd inflate the inner tube then inflate main tube which would crush inner... Would it reinflate once outer deflated?

Poly · 19 August 2014, 07:48

Shiny - stop leading the guy down an expensive dead end. He has two chambers on a 40 year old boat. Trying to bodge that to be safer with any of the ideas suggested is crazy.

The boat is probably fine for close inshore stuff or use with friends around, but sell it and get something appropriate if going a mile offshore.

HighlandR · 19 August 2014, 10:25

Shiny, about reducing the consequence score - on this current boat I can't think of anything safer than having the 2 tubes filled with some type of foam, just like a buoyancy aid / life jacket.

Other than being unable to fold it back up again, I can't think of any other negative point.

The plus points I see are :

It will make the boat 100% unsinkable
It will help retain the shape and be buoyant enough to support us both and the engine even if both tubes deflate.
It would also remove the urgent need to replace valve locations ( knowing the thing will still float - it then wouldn't be a desperate panic to start pumping a tube back up )

If I were to spend £35 on these 20mm balls and use them as a filler ( the valves are 25mm dia so will fit ) what are the bad points about doing that ?

I'm asking myself - would I rather be in a 3 tube hollow inflatable or a 2 tube filled with foam?

I have a gas life jacket here and wear it often as I believe the chances of the thing bursting are very remote and negligible, but when on the water I still prefer to wear the older foam vests and PFD's.

Is the sib any different ?